The typical clinical manifestation of lower extremity deep vein thrombosis is often swelling and pain in the unilateral lower extremity (left lower extremity is more common). However, the early stage of thrombosis can also have no obvious symptoms, causing some patients with venous thrombosis to delay the best time for treatment, or when acute venous thrombosis occurs, standardized treatment methods are not taken in time, and the necessary preventive measures are not used when the thrombosis turns into the chronic stage, all these factors can easily lead to the occurrence of sequelae. Therefore, one of the main treatment principles of acute lower extremity DVT is to remove the formed thrombus as much as possible to protect the DVT valve and prevent the sequelae, so timely diagnosis, standardized treatment and strengthening the rehabilitation of the chronic phase are the keys to prevent the sequelae of lower extremity DVT. Acute phase of lower limb deep vein thrombosis. Post-thrombotic syndrome (PTS) of lower limb deep vein thrombosis.